A deaerator must be installed a certain height above the feedwater pump. What is that height?

A deaerator must be installed a certain height above the feedwater pump. What is that height?

• A. Thirty feet
• B. Twenty feet
• C. Forty feet
• D. Fifty feet

Answer: (A)

Providing enough suction head to the feedwater pump is the key idea here. Placing the deaerator higher than the pump creates hydrostatic pressure at the pump suction so the pump draws water rather than air, helping maintain priming and prevent cavitation. About thirty feet of vertical separation is a practical amount in many systems, giving a reliable suction head under typical operating conditions without overcomplicating installation. If the deaerator were much lower, the pump could struggle to maintain flow or suffer cavitation; if much higher, the extra height offers little benefit once a sufficient suction margin is reached.

Providing enough suction head to the feedwater pump is the key idea here. Placing the deaerator higher than the pump creates hydrostatic pressure at the pump suction so the pump draws water rather than air, helping maintain priming and prevent cavitation. About thirty feet of vertical separation is a practical amount in many systems, giving a reliable suction head under typical operating conditions without overcomplicating installation. If the deaerator were much lower, the pump could struggle to maintain flow or suffer cavitation; if much higher, the extra height offers little benefit once a sufficient suction margin is reached.